<template>
  <div class="swiper-container" ref="imgSwiper">
    <div class="swiper-wrapper">
      <div class="swiper-slide" v-for="(img,index) in skuImageList" :key="img.id" @click="choosedIndex(index)">
        <img :src="img.imgUrl" :class="{active:imgIndex === index}" />
      </div>
    </div>
    <div class="swiper-button-next"></div>
    <div class="swiper-button-prev"></div>
  </div>
</template>

<script>
import Swiper from "swiper";
export default {
  name: "ImageList",
  data() {
    return {
      imgIndex:0
    }
  },
  props: ["skuImageList"],
  methods: {
    choosedIndex(index) {
      this.imgIndex = index
      this.$bus.$emit('updateIndex',index)
    }
  },
  watch: {
    // 该组件第一次挂载的时候去请求数据了，请求数据是异步的，挂载完数据还没有返回，没有数据就没有轮播结构，所以要监视bannerList的变化，一旦数据回来了，我们就要准备生成swiper实例，但是数据变化的，页面要更新，页面更新也是异步的，如果我们直接创建swiper实例，这个时候页面还没有生成轮播结构，vue内部给我们提供了一个方法$nextTick,这个方法是页面生成真实dom后才会执行，所以在这个函数内部去new我们的swiper实例，这个时候既有数据有有轮播结构
    skuImageList: {
      handler(newVal, oldVal) {
        if (!newVal.length) {
          return;
        }
        this.$nextTick(() => {
          new Swiper(this.$refs.imgSwiper, {
            slidesPerView:3, //一屏显示多少张
            slidesPerGroup:2,  //一次移动走多少张
            navigation: {
              // 获取左右按钮的容器
              nextEl: ".swiper-button-next",
              prevEl: ".swiper-button-prev",
            },
          });
        });
      },
      immediate: true,
    },
  },
};
</script>

<style lang="less" scoped>
.swiper-container {
  height: 56px;
  width: 412px;
  box-sizing: border-box;
  padding: 0 12px;

  .swiper-slide {
    width: 56px;
    height: 56px;

    img {
      width: 100%;
      height: 100%;
      border: 1px solid #ccc;
      padding: 2px;
      width: 50px;
      height: 50px;
      display: block;

      &.active {
        border: 2px solid #f60;
        padding: 1px;
      }

      &:hover {
        border: 2px solid #f60;
        padding: 1px;
      }
    }
  }

  .swiper-button-next {
    left: auto;
    right: 0;
  }

  .swiper-button-prev {
    left: 0;
    right: auto;
  }

  .swiper-button-next,
  .swiper-button-prev {
    box-sizing: border-box;
    width: 12px;
    height: 56px;
    background: rgb(235, 235, 235);
    border: 1px solid rgb(204, 204, 204);
    top: 0;
    margin-top: 0;
    &::after {
      font-size: 12px;
    }
  }
}
</style>